用稳态光谱和时间分辨光谱技术研究了空穴传输材料对CdSe/ZnSe与CdSe/ZnS核壳量子点的荧光影响。结果表明,空穴传输材料对量子点有较强的猝灭作用,随空穴传输材料分子浓度的增加,量子点的荧光强度明显地被猝灭,同时量子点的荧光寿命也被减短。两种不同空穴传输分子对CdSe/ZnSe量子点的荧光猝灭明显不同。在与相同空穴传输分子相互作用时,包覆ZnS壳层的CdSe核壳量子点荧光猝灭效率明显低于包覆ZnSe壳层的CdSe核壳量子点。量子点的荧光猝灭过程可以解释为静态猝灭和动态猝灭过程,其中静态猝灭来源于量子点表面与空穴传输材料间相互作用,而动态猝灭则主要来源于量子点到空穴传输材料的空穴转移过程。实验结果表明空穴传输材料的种类以及核壳量子点的壳层结构都对其荧光猝灭效应起关键作用。
Photoluminescence quenching of colloidal CdSe core/shell quantum dots in the presence of hole transporting materials was studied by means of steady state and time resolved photoluminescence spectroscopy.With increasing hole transporting materials concentration in the CdSe core/shell quantum dot solution,the photoluminescence intensity and lifetime decreased gradually.The photoluminescence quenching of CdSe/ZnSe quantum dots with adding hole transporting material N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine(NPB)is more efficient than N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine(TPD).And compared with CdSe core/shell quantum dots with ZnSe shell,the ZnS shell is an effective one on the surface of CdSe quantum dots for reducing photoluminescence quenching efficiency when interacting with hole transporting material TPD.Based on the analysis,there are two pathways in the photoluminescence quenching process:static quenching and dynamic quenching.The static quenching results from the decrease in the number of the emitting centers,and the dynamic quenching is caused by the hole transfer from quantum dots to hole transporting materials molecules.The efficiency of the photoluminescence quenching in CdSe core/shell quantum dots is strongly dependent on the structure of the shells and the HOMO levels of the hole transporting materials.The results are important for understanding the nature of quantum dots surface and the interaction of quantum dots and hole transporting materials.